1. Field of the Invention
The present invention relates to a composite type thin-film magnetic head comprising an inductive write head element and a magnetoresistive (MR) read head element that has a current-perpendicular-to-plane (CPP) structure where a sense current flows in a direction perpendicular to surfaces of layers.
2. Description of the Related Art
Recently, in order to satisfy the demand for larger capacity and more downsizing of a hard disk drive apparatus (HDD), higher recording density in a magnetic disk and more miniaturization of a head gimbal assembly (HGA) including a magnetic head are intended to be achieved.
The more miniaturization of the HGA, however, causes a problem of crosstalk between a writing side and a reading side. Especially, more miniaturization of a magnetic head element causes an increase in density of a current flowing through the element due to a decrease in a cross section area of the element, as well as a decrease in heat dispersion. Moreover, higher frequency for writing results in a steep change in voltage applied to the write head element. Consequently, a crosstalk occurs from the writing side to the reading side, which brings a tendency toward degradation of the characteristics in the read head element. Especially in a tunnel magnetoresistive (TMR) read head element, the crosstalk voltage causes pinholes to be formed in a barrier layer, which result in dielectric breakdown and bring a great degradation of the reading characteristics due to a decrease in an electrical resistance of the element.
A technique to reduce a crosstalk between trace conductors in the writing side and in the reading side is proposed in Klaas B. Klaassen et al., “Write-to-Read Coupling”, IEEE Trans. Magn. Vol. 38, pp61-67, January 2002, which analyzes a coupling mechanism between the trace conductors formed on a suspension. In the description, it is concluded that almost all crosstalk is caused by the coupling between the trace conductors, not by the inner coupling in the magnetic head.
However, the inventors achieve the present invention in consequence of analyses and investigations based on the thought that the inner coupling must have a great influence on the crosstalk between the writing and reading sides, as well as the coupling between the trace conductors.